ACQUISITION OF THE MENTAL STATE VERB KNOW BY 2-YEAR-OLD TO 5-YEAR-OLDCHILDREN

The production of the cognitive internal stat word know by four 2- to 5-year-old children and their parents was examined. The levels of mean ing of cognitive words can be categorized hierarchically along the dim ensions of conceptual difficulty and abstractness (see Booth & Hall, 1 995). The present study found that children and their parents expresse d low levels of meaning less frequently, whereas they expressed high l evels of meaning more frequently as a function of age. The children's use of know was also correlated positively with (1) their number of di fferent words produced suggesting that cognitive words are related to more general semantic processes, and (2) with parental use of those sa me cognitive words suggesting that parental linguistic input may be an important mechanism in cognitive word acquisition. Finally, young chi ldren tended to use know more to refer to themselves than to refer to others, whereas their parents tended to use know equally to refer to s elf and others. The importance of cognitive words in a theory of langu age acquisition is discussed.